package main

// Drafting and confirming clauses at the import (novox/hq ADR 0290 rule 8, to-be 55 §7). For a decision whose
// Decision section is prose, one judgement drafts its clauses: the section in, numbered statements out, each one
// sentence saying nothing the section does not. They are kept `drafted`, and never served as in force. A second
// judgement, a separate call that sees only the record and the drafts, answers per clause whether the record says
// exactly that: a clause it accepts becomes `confirmed`, one it rejects stays `drafted` with the reason. Which
// clause of an older record a supersedes-in-part changes is judged and confirmed the same way. When every record
// of a topic has been through both, the operator is told once, with the counts. `return` sends a record back to
// be drafted again.
//
// The judgements are the agent's on this node (claude-code.claude_code_judge, ADR 0278): no tools, no session,
// at most 25 seconds each, one at a time. The worker takes one step at a time in the background.

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"strconv"
	"strings"
	"time"
)

// DefaultJudgeModel is the model the judgements ask unless the settings name another.
const DefaultJudgeModel = "sonnet"

// MostDraftTries is how many times a record's drafting is tried before it is left failed, said by its get.
const MostDraftTries = 3

var draftSchema = map[string]any{
	"type": "object",
	"properties": map[string]any{
		"clauses": map[string]any{"type": "array", "items": map[string]any{
			"type": "object",
			"properties": map[string]any{
				"lead": map[string]any{"type": "string", "description": "a few words naming what is decided, ending with a full stop"},
				"text": map[string]any{"type": "string", "description": "the one sentence of the statement, after the lead"},
			},
			"required": []string{"lead", "text"},
		}},
	},
	"required": []string{"clauses"},
}

var confirmSchema = map[string]any{
	"type": "object",
	"properties": map[string]any{
		"verdicts": map[string]any{"type": "array", "items": map[string]any{
			"type": "object",
			"properties": map[string]any{
				"clause": map[string]any{"type": "integer"},
				"exact":  map[string]any{"type": "boolean", "description": "true when the record says exactly this, nothing more"},
				"reason": map[string]any{"type": "string", "description": "when not exact: what the record says instead"},
			},
			"required": []string{"clause", "exact"},
		}},
	},
	"required": []string{"verdicts"},
}

var whichSchema = map[string]any{
	"type": "object",
	"properties": map[string]any{
		"clauses": map[string]any{"type": "array", "items": map[string]any{"type": "integer"},
			"description": "the numbers of the older record's clauses the newer record replaces part of"},
		"reason": map[string]any{"type": "string"},
	},
	"required": []string{"clauses", "reason"},
}

var whichConfirmSchema = map[string]any{
	"type": "object",
	"properties": map[string]any{
		"exact":  map[string]any{"type": "boolean"},
		"reason": map[string]any{"type": "string"},
	},
	"required": []string{"exact", "reason"},
}

// MostDraftSource is the most text a record is drafted from in one judgement, which takes at most 64 KiB.
const MostDraftSource = 48 << 10

// draftSource is what a record's clauses are drafted from: its Decision section, or, for a record that has none
// (hq issue 487), what it decides across its sections — all but its preamble, consequences and references.
func draftSource(r *Record) (text string, whole bool) {
	if section, ok := decisionSection(r); ok && strings.TrimSpace(section) != "" {
		return section, false
	}
	var b strings.Builder
	for _, s := range r.Sections {
		name := strings.ToLower(strings.TrimSpace(s.Name))
		if name == "preamble" || strings.HasPrefix(name, "consequences") || strings.HasPrefix(name, "references") || strings.TrimSpace(s.Text) == "" {
			continue
		}
		fmt.Fprintf(&b, "## %s\n\n%s\n\n", s.Name, strings.TrimSpace(s.Text))
	}
	return strings.TrimSpace(b.String()), true
}

// sourceName is how a question names what it hands the judgement.
func sourceName(whole bool) string {
	if whole {
		return "The record's sections"
	}
	return "The Decision section"
}

// DraftQuestion is the first judgement's question: the record's Decision section — or, where it has none, its
// sections — and nothing else of the mesh.
func DraftQuestion(r *Record, section, returned string, whole bool) string {
	var b strings.Builder
	if whole {
		fmt.Fprintf(&b, "Below are the sections of a decision record, %s: %q. It has no Decision section: what it decides is written "+
			"as prose across its sections. Write what it decides as numbered clauses: each one statement, one sentence, with a lead of a "+
			"few words naming what is decided. A clause says nothing the sections do not say: no inference, no context from elsewhere, "+
			"nothing added. Every decision the sections make is in one clause; a sentence that only explains, or describes what was, is "+
			"in none. Keep the record's own words where you can.\n", r.Key(), r.Title)
		if returned != "" {
			fmt.Fprintf(&b, "\nAn earlier draft was sent back, with this reason: %s\n", returned)
		}
		b.WriteString("\n" + sourceName(true) + ":\n\n" + section)
		return b.String()
	}
	fmt.Fprintf(&b, "Below is the Decision section of a decision record, %s: %q. It is written as prose. Write what it decides as numbered "+
		"clauses: each one statement, one sentence, with a lead of a few words naming what is decided. A clause says nothing the section "+
		"does not say: no inference, no context from elsewhere, nothing added. Every decision the section makes is in one clause; a "+
		"sentence that only explains is in none. Keep the section's own words where you can.\n", r.Key(), r.Title)
	if returned != "" {
		fmt.Fprintf(&b, "\nAn earlier draft was sent back, with this reason: %s\n", returned)
	}
	b.WriteString("\nThe Decision section:\n\n" + section)
	return b.String()
}

// ConfirmQuestion is the second judgement's question: the record and the drafts, nothing else.
func ConfirmQuestion(r *Record, section string, drafts []Clause, whole bool) string {
	var b strings.Builder
	what := "the Decision section of a decision record"
	if whole {
		what = "the sections of a decision record that has no Decision section"
	}
	fmt.Fprintf(&b, "Below are %s, %s: %q, and clauses drafted from it by someone else. For each "+
		"clause, answer whether the text says exactly that: exact is true only when the clause says nothing the text does not, "+
		"and leaves out nothing that changes its meaning. When it is not exact, say in reason what the text says instead.\n\n"+
		"%s:\n\n%s\n\nThe drafted clauses:\n\n", what, r.Key(), r.Title, sourceName(whole), section)
	for _, c := range drafts {
		fmt.Fprintf(&b, "%d. %s\n", c.N, c.Text)
	}
	return b.String()
}

func (k *KB) judgeModel() string {
	if m := strings.TrimSpace(k.settings().JudgeModel); m != "" {
		return m
	}
	return DefaultJudgeModel
}

// DraftStep takes one step of the drafting and confirming: the first record waiting to be drafted or confirmed,
// then the first changes link whose clause is not yet judged. It answers what it did, or "" when nothing waits.
func (k *KB) DraftStep() (string, error) {
	if k.Judge == nil || strings.EqualFold(strings.TrimSpace(k.settings().Drafting), "off") {
		return "", nil
	}
	ctx := context.Background()
	all, err := k.Store.All(ctx)
	if err != nil {
		return "", err
	}
	for _, e := range all {
		d := e.Current.Drafting
		if d == nil || d.State == DraftDone || (d.State == DraftFailed && d.Tries >= MostDraftTries) {
			continue
		}
		if d.State == DraftFailed && k.now().Sub(d.At) < time.Duration(d.Tries)*10*time.Minute {
			continue
		}
		return k.draftOne(ctx, e.Current.Key())
	}
	for _, e := range all {
		if !e.Current.Accepted() {
			continue
		}
		for i, l := range e.Current.Links {
			if l.Kind == LinkChanges && (l.Source == LinkPending || l.Source == SourceDrafted) && !l.Unresolved {
				return k.judgeChange(ctx, e.Current.Key(), i)
			}
		}
	}
	return "", nil
}

// draftOne drafts or confirms one record's clauses, under the write lock only to read and to write.
func (k *KB) draftOne(ctx context.Context, key Key) (string, error) {
	k.mu.Lock()
	e, err := k.Store.Get(ctx, key)
	k.mu.Unlock()
	if err != nil || e == nil {
		return "", err
	}
	r := e.Current.Clone()
	section, whole := draftSource(r)
	if section == "" || len(section) > MostDraftSource {
		why := fmt.Sprintf("no Decision section, and its sections hold %d bytes of what it decides, more than one judgement takes (%d): "+
			"it has no clauses", len(section), MostDraftSource)
		if section == "" {
			why = "no Decision section, and no section saying what it decides: it has no clauses"
		}
		r.Drafting = &Drafting{State: DraftDone, Reason: why, At: k.now()}
		return k.saveDraft(ctx, e, r, EventDrafted, why)
	}
	model := k.judgeModel()
	fail := func(step string, err error) (string, error) {
		// Tried again after a pause that grows with each try, at the step it failed at, up to MostDraftTries.
		r.Drafting.State, r.Drafting.Reason, r.Drafting.At = DraftFailed, step+": "+err.Error(), k.now()
		r.Drafting.Tries++
		_, serr := k.saveDraft(ctx, e, r, EventDrafted, step+" failed: "+err.Error())
		if serr != nil {
			return "", serr
		}
		return "", fmt.Errorf("%s %s: %v", step, key, err)
	}
	if r.Drafting == nil {
		r.Drafting = &Drafting{State: DraftWaiting}
	}
	// A failed record goes back to the step it failed at: confirming when it holds drafts, drafting otherwise.
	confirming := r.Drafting.State == DraftDrafted || (r.Drafting.State == DraftFailed && hasDrafts(r))
	if !confirming {
		answer, by, err := k.Judge(DraftQuestion(r, section, r.Drafting.Returned, whole), draftSchema, model)
		if err != nil {
			return fail("drafting", err)
		}
		var drafted struct {
			Clauses []struct {
				Lead string `json:"lead"`
				Text string `json:"text"`
			} `json:"clauses"`
		}
		if err := json.Unmarshal(answer, &drafted); err != nil || len(drafted.Clauses) == 0 {
			return fail("drafting", errors.New("the judgement drafted no clause"))
		}
		r.Clauses = nil
		for i, c := range drafted.Clauses {
			lead := strings.TrimSpace(strings.Trim(c.Lead, "* "))
			if !strings.HasSuffix(lead, ".") {
				lead += "."
			}
			r.Clauses = append(r.Clauses, Clause{N: i + 1, Text: "**" + lead + "** " + strings.TrimSpace(c.Text),
				Status: clauseStatusOf(r.Status), Source: SourceDrafted})
		}
		r.Drafting = &Drafting{State: DraftDrafted, Drafter: by, Returned: r.Drafting.Returned, Tries: r.Drafting.Tries, At: k.now()}
		return k.saveDraft(ctx, e, r, EventDrafted, fmt.Sprintf("%d clauses drafted by %s", len(r.Clauses), by))
	}
	answer, by, err := k.Judge(ConfirmQuestion(r, section, r.Clauses, whole), confirmSchema, model)
	if err != nil {
		return fail("confirming", err)
	}
	var verdicts struct {
		Verdicts []struct {
			Clause int    `json:"clause"`
			Exact  bool   `json:"exact"`
			Reason string `json:"reason"`
		} `json:"verdicts"`
	}
	if err := json.Unmarshal(answer, &verdicts); err != nil {
		return fail("confirming", errors.New("the judgement answered no verdicts"))
	}
	confirmed := 0
	for i := range r.Clauses {
		r.Clauses[i].Unconfirmed = "the second judgement gave no verdict on it"
		for _, v := range verdicts.Verdicts {
			if v.Clause != r.Clauses[i].N {
				continue
			}
			if v.Exact {
				r.Clauses[i].Source, r.Clauses[i].Unconfirmed = SourceConfirmed, ""
				confirmed++
			} else {
				r.Clauses[i].Unconfirmed = strings.TrimSpace(v.Reason)
				if r.Clauses[i].Unconfirmed == "" {
					r.Clauses[i].Unconfirmed = "not exact"
				}
			}
		}
	}
	r.Drafting.State, r.Drafting.Checker, r.Drafting.At, r.Drafting.Reason = DraftDone, by, k.now(), ""
	said, err := k.saveDraft(ctx, e, r, EventConfirmed, fmt.Sprintf("%d of %d drafted clauses confirmed by %s", confirmed, len(r.Clauses), by))
	if err != nil {
		return "", err
	}
	k.tellTopic(ctx, r.Topic)
	return said, nil
}

func hasDrafts(r *Record) bool {
	for _, c := range r.Clauses {
		if c.Source == SourceDrafted {
			return true
		}
	}
	return false
}

func (k *KB) saveDraft(ctx context.Context, e *Entry, r *Record, event, why string) (string, error) {
	k.mu.Lock()
	defer k.mu.Unlock()
	by := "the knowledge base"
	if r.Drafting != nil && event == EventDrafted && r.Drafting.Drafter != "" {
		by = r.Drafting.Drafter
	}
	if r.Drafting != nil && event == EventConfirmed && r.Drafting.Checker != "" {
		by = r.Drafting.Checker
	}
	if err := k.Store.Save(ctx, Version{By: by, At: k.now(), Why: why, Record: r}, true, false, e.Revision); err != nil {
		return "", fmt.Errorf("%s could not be kept (%v)", r.Key(), err)
	}
	k.emit(event, r, by, why, e.Versions+1)
	return r.Key().String() + ": " + why, nil
}

// tellTopic tells the operator, once, when every prose record of a topic has been drafted and confirmed.
func (k *KB) tellTopic(ctx context.Context, topic string) {
	if k.Notify == nil || topic == "" {
		return
	}
	all, err := k.Store.All(ctx)
	if err != nil {
		return
	}
	records, confirmed, drafted := 0, 0, 0
	for _, e := range all {
		r := e.Current
		if r.Topic != topic || r.Drafting == nil {
			continue
		}
		if r.Drafting.State != DraftDone {
			return
		}
		records++
		for _, c := range r.Clauses {
			if c.Source == SourceConfirmed {
				confirmed++
			} else if c.Source == SourceDrafted {
				drafted++
			}
		}
	}
	if records == 0 {
		return
	}
	first, err := k.Store.Told(ctx, topic)
	if err != nil || !first {
		return
	}
	summary := fmt.Sprintf("The clauses of %d prose decisions on %s are drafted and checked: %d confirmed, %d still drafted.", records, topic, confirmed, drafted)
	explanation := "A second judgement confirmed each clause against its record; a clause still drafted is never served as in force. " +
		"You may send any record back with the knowledge base's return, and its clauses are drafted again. Nothing needs you otherwise."
	if err := k.Notify("knowledge.clauses."+strings.ReplaceAll(topic, " ", "-"), summary, "Clauses drafted for "+topic, explanation, ""); err != nil {
		k.logf("[mesh-knowledge] the operator could not be told about %s's clauses: %v", topic, err)
	}
}

// judgeChange judges, then confirms, which clause of an older record a supersedes-in-part of hq changes.
func (k *KB) judgeChange(ctx context.Context, from Key, i int) (string, error) {
	k.mu.Lock()
	e, err := k.Store.Get(ctx, from)
	var t *Entry
	if err == nil && e != nil && i < len(e.Current.Links) {
		if to, ok := e.Current.Links[i].To.Record(); ok {
			t, err = k.Store.Get(ctx, to)
		}
	}
	k.mu.Unlock()
	if err != nil || e == nil || t == nil {
		return "", err
	}
	r := e.Current.Clone()
	l := &r.Links[i]
	older := t.Current
	served := 0
	for _, c := range older.Clauses {
		if c.Source != SourceDrafted {
			served++
		}
	}
	if served == 0 {
		return "", nil // the older record's clauses are not confirmed yet: judged once they are
	}
	model := k.judgeModel()
	newer, whole := draftSource(r)
	var b strings.Builder
	fmt.Fprintf(&b, "%s says it replaces part of an older record, %s. Below are the clauses of %s and %s of %s.\n\n", r.Key(), older.Key(), older.Key(),
		strings.ToLower(sourceName(whole)), r.Key())
	for _, c := range older.Clauses {
		fmt.Fprintf(&b, "%d. %s\n", c.N, c.Text)
	}
	fmt.Fprintf(&b, "\n%s of %s:\n\n%s\n", sourceName(whole), r.Key(), newer)
	if l.Source == LinkPending {
		answer, by, err := k.Judge(b.String()+"\nWhich of the older record's clauses does the newer record replace part of? Name their numbers.", whichSchema, model)
		if err != nil {
			return "", fmt.Errorf("judging which clause %s changes: %v", r.Key(), err)
		}
		var which struct {
			Clauses []int  `json:"clauses"`
			Reason  string `json:"reason"`
		}
		if json.Unmarshal(answer, &which) != nil || len(which.Clauses) == 0 || older.Clause(which.Clauses[0]) == nil {
			return "", fmt.Errorf("judging which clause %s changes: the judgement named no clause of %s", r.Key(), older.Key())
		}
		base := *l
		l.To.Clause, l.Source = which.Clauses[0], SourceDrafted
		for _, n := range which.Clauses[1:] {
			if older.Clause(n) != nil {
				extra := base
				extra.To.Clause, extra.Source = n, SourceDrafted
				r.Links = append(r.Links, extra)
			}
		}
		return k.saveLinks(ctx, e, r, by, fmt.Sprintf("which clause of %s it changes drafted: §%s (%s)", older.Key(), joinInts(which.Clauses), which.Reason))
	}
	answer, by, err := k.Judge(b.String()+fmt.Sprintf("\nA first judgement said %s replaces part of clause %d of %s. Is that exact?", r.Key(), l.To.Clause, older.Key()), whichConfirmSchema, model)
	if err != nil {
		return "", fmt.Errorf("confirming which clause %s changes: %v", r.Key(), err)
	}
	var v struct {
		Exact  bool   `json:"exact"`
		Reason string `json:"reason"`
	}
	if json.Unmarshal(answer, &v) != nil {
		return "", fmt.Errorf("confirming which clause %s changes: no verdict", r.Key())
	}
	if !v.Exact {
		clause := l.To.Clause
		l.To.Clause, l.Source = 0, SourceDrafted+": not confirmed"
		return k.saveLinks(ctx, e, r, by, fmt.Sprintf("that it changes %s §%d was not confirmed: %s", older.Key(), clause, v.Reason))
	}
	l.Source = SourceConfirmed
	said, err := k.saveLinks(ctx, e, r, by, fmt.Sprintf("that it changes %s §%d confirmed by %s", older.Key(), l.To.Clause, by))
	if err != nil {
		return "", err
	}
	// The older clause is changed now, as an acceptance would have made it.
	k.mu.Lock()
	defer k.mu.Unlock()
	t, err = k.Store.Get(ctx, older.Key())
	if err != nil || t == nil {
		return said, err
	}
	c := t.Current.Clone()
	if cl := c.Clause(l.To.Clause); cl != nil && cl.Status == ClauseInForce {
		cl.Status = ClauseChanged
		cl.ChangedBy = append(cl.ChangedBy, r.Key().String())
		what := fmt.Sprintf("§%d changed by %s (as hq said, its clause judged and confirmed)", l.To.Clause, r.Key())
		if err := k.Store.Save(ctx, Version{By: by, At: k.now(), Why: what, Record: c}, true, false, t.Revision); err != nil {
			return said, err
		}
		k.emit(EventChanged, c, by, what, t.Versions+1)
	}
	return said, nil
}

func (k *KB) saveLinks(ctx context.Context, e *Entry, r *Record, by, why string) (string, error) {
	k.mu.Lock()
	defer k.mu.Unlock()
	if err := k.Store.Save(ctx, Version{By: by, At: k.now(), Why: why, Record: r}, true, false, e.Revision); err != nil {
		return "", fmt.Errorf("%s could not be kept (%v)", r.Key(), err)
	}
	event := EventDrafted
	if strings.Contains(why, "confirmed") {
		event = EventConfirmed
	}
	k.emit(event, r, by, why, e.Versions+1)
	return r.Key().String() + ": " + why, nil
}

func joinInts(ns []int) string {
	s := make([]string, len(ns))
	for i, n := range ns {
		s[i] = strconv.Itoa(n)
	}
	return strings.Join(s, ", §")
}

// Return sends a record's drafted or confirmed clauses back to be drafted again, with the reason, which the next
// drafting reads.
func (k *KB) Return(caller string, key Key, reason string) (map[string]any, error) {
	ctx := context.Background()
	reason = strings.TrimSpace(reason)
	if reason == "" {
		return nil, errors.New("return needs reason: what is wrong with the clauses drafted")
	}
	k.mu.Lock()
	defer k.mu.Unlock()
	e, err := k.Store.Get(ctx, key)
	if err != nil {
		return nil, err
	}
	if e == nil {
		return nil, fmt.Errorf("the knowledge base holds no %s", key)
	}
	r := e.Current.Clone()
	if r.Drafting == nil {
		return nil, fmt.Errorf("%s's clauses were written by its author, not drafted: a written clause is changed by a new record", key)
	}
	all, err := k.Store.All(ctx)
	if err != nil {
		return nil, err
	}
	if held := clauseHolds(r, all); len(held) > 0 {
		return nil, fmt.Errorf("%s is not returned: drafting it again would number its clauses anew, and these hold them to their numbers: %s. "+
			"A clause keeps its number once another record links it (novox/hq issue 494). To say a drafted clause is wrong "+
			"or no longer holds, propose a record that changes it (changes %s §N)", key, strings.Join(held, "; "), strings.TrimPrefix(key.String(), "ADR "))
	}
	r.Clauses = nil
	r.Drafting = &Drafting{State: DraftWaiting, Returned: reason, At: k.now()}
	why := "returned to be drafted again: " + reason
	if err := k.Store.Save(ctx, Version{By: caller, At: k.now(), Why: why, Record: r}, true, false, e.Revision); err != nil {
		return nil, err
	}
	k.emit(EventReturned, r, caller, why, e.Versions+1)
	return map[string]any{"record": key.String(), "says": fmt.Sprintf("%s's clauses are taken back and will be drafted again, with your reason; until then it serves none.", key)}, nil
}

// clauseHolds is what holds a record's clauses to their numbers: each clause another record changed or superseded,
// and each link of another record, served or proposed, that names one of its clauses. A redraft numbers the clauses
// anew, so a record any of these name is never returned: its links would point at other clauses.
func clauseHolds(r *Record, all []*Entry) []string {
	var out []string
	for _, c := range r.Clauses {
		if len(c.ChangedBy) > 0 && (c.Status == ClauseChanged || c.Status == ClauseSuperseded) {
			out = append(out, fmt.Sprintf("§%d is %s by %s", c.N, c.Status, strings.Join(c.ChangedBy, ", ")))
		}
	}
	key := r.Key()
	seen := map[string]bool{}
	for _, e := range all {
		for _, v := range []*Record{e.Current, e.Pending} {
			if v == nil || v.Key() == key || v.Status == StatusWithdrawn {
				continue
			}
			for _, l := range v.Links {
				to, ok := l.To.Record()
				if !ok || to != key || l.To.Clause == 0 {
					continue
				}
				s := fmt.Sprintf("%s (%s) %s §%d", v.Key(), v.Status, l.Kind, l.To.Clause)
				if !seen[s] {
					seen[s] = true
					out = append(out, s)
				}
			}
		}
	}
	return out
}